About a month ago immediately following sex the head of my penis and what felt like inside the urethral opening was sore. It went away after a few days and has been off and on over the course of the month. But mainly off. It happened again a few days ago after sex and masturbation. It's gotten better to where it's like a dull soreness or even pinching sensation. I've looked online and of course the first thing that pops up is an std. She's been tested and is clear. My results are pending. That said I find it hard to believe it's something more than an irritation. Any thoughts? There are no other symptoms - no issue urinating, ejaculating, no discoloration of penis or urine.